Well testing is a tool for the exploration and planning of hydrocarbon field development. Well testing can provide a wide range of reservoir information, such as well productivity, permeability, pressure, formation damage, and drainage area. Furthermore, the sampling of reservoir fluids during well testing can provide information that is used for designing well and surface facilities associated with reservoir development. Drawdown and build-up well testing are common in conventional reservoirs to obtain this information. Drawdown and build-up testing includes drilling a wellbore and shutting in the well for a period of time to allow the wellbore pressure to build. After a sufficient pressure is built up, hydrocarbon fluid may be produced for testing purposes. Surface parameters, such as well head pressure and temperature, separator conditions, sand presence, and preliminary characterization of fluids (for example, oil gravity, gas gravity, and water salinity) can be measured. Downhole pressure and temperature can be measured using a downhole pressure and temperature gauges during both drawdown and build-up phases.